The background description provided herein is for the purpose of generally presenting the context of the present invention. The subject matter discussed in the background of the invention section should not be assumed to be prior art merely as a result of its mention in the background of the invention section. Similarly, a problem mentioned in the background of the invention section or associated with the subject matter of the background of the invention section should not be assumed to have been previously recognized in the prior art. The subject matter in the background of the invention section merely represents different approaches, which in and of themselves may also be inventions. Work of the presently named inventors, to the extent it is described in the background of the invention section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present invention.
In a conventional refrigerator, when a cooler is defrosted, there is a problem that hot air surrounding the cooler heated by a defrost heater flows into a storage chamber to raise the temperature in the storage chamber. Therefore, to prevent hot air in a defrosting operation from entering into the storage chamber, a known solution is to dispose an air door in a cooling air duct and close the air door in the defrosting operation (e.g., disclosed in Japanese Patent Publication No. JP 2009-250476).
FIG. 9 is a front view of an air duct structure of a refrigerator 100 disclosed in Japanese Patent Publication No. JP 2009-250476. In the refrigerator 100, inlet air doors 105, 106, 107 and 108 are respectively disposed in cool air supply air duct 101, 102, 103 and 104 that send cool air cooled by the cooler to the storage chamber. In addition, cool air return air ducts 109, 110 and 111 through which the cool air returns from the storage chamber to the cooler are respectively provided with outlet air doors 113, 114 and 115. Furthermore, a cool air return air duct (not shown) from a freezing chamber 112 is provided with an outlet air door 116. Moreover, in the defrosting operation, all or part of the inlet air doors 105, 106, 107 and 108 and the outlet air doors 113, 114, 115 and 116 are closed.
Another known solution, as shown in FIGS. 10A and 10B, is to dispose forced draft fans 205 and 305 in a cool air blowout port leading to the storage chamber and dispose air volume control mechanisms 200 and 300 on the forced draft fans 205 and 305 (e.g., disclosed in Japanese Patent Publication No. JP 2006-300427).
The air volume control mechanism 200 shown in FIG. 10A includes an air outside frame of the axial forced draft fan 205 mounted to one side of multiple openable and closeable plates 201, to open and close the openable and closeable plates 201 by means of driving of a small motor 204 connected via a connecting plate 202 and a rotating plate 203.
In addition, in the air volume control mechanism 300 shown in FIG. 10B, a suction side of the axial forced draft fan 305 is provided with a wind ring shield 301. The wind ring shield 301 is opened and closed by means of a solenoid 304 connected via an operating plate 302 and a connecting shaft 303.
However, as shown in FIG. 9, in the prior art refrigerators which dispose air doors in cooling air ducts, for various refrigerators designed to have different capacity and functions, it is necessary to design respective air ducts and air doors corresponding to the air ducts for each model. Therefore, if air doors adapted to various models of air ducts are disposed, the kinds of the air doors will increase, to become a multi-specification & small batch production manner, and there is a problem that development cost and production cost of the air doors increase.
In addition, as shown in FIG. 10A, in the structure that the air volume control mechanism 200 is mounted to the forced draft fan 205, there is a problem that the air volume control mechanism 200 has great flow resistance. That is, when air flowing on the air outside of the axial forced draft fan forms a rotational flow that takes the vicinity of a fan rotating shaft as a center shaft, the rotational flow will be hindered as the air volume control mechanism 200 is a structure that arranges multiple open and close plates 201 in parallel.
In addition, when the wind ring shield 301 shown in FIG. 10B is used at the air outside of the forced draft fan, there is a problem that an air-out portion of the forced draft fan has great pressure loss. That is, when air flowing on the air outside of the forced draft fan in the refrigerator has a characteristic that flow velocity in a turning radius direction is greater than that in a fan rotating shaft direction, the wind ring shield 301 will hinder flowing in the turning radius direction.
Moreover, in use of the structure of the openable and closeable plates 201 shown in FIG. 10A and the structure of the wind ring shield 301 shown in FIG. 10B, it is likely that attached moisture freezes to hinder actions thereof.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.